Not applicable.
Not applicable.
Not applicable.
The present invention relates to offshore communications systems. More particularly, the present invention relates to methods and apparatus for connecting a fiberoptic cable to a sub sea connection. Additionally, and furthermore, the present invention relates to methods for establishing a communications connection between offshore structures and sub sea connections.
There is a need for fiberoptic connections to be made sub sea by using underwater mateable connectors. These underwater connectors are available from various manufacturers. These connections are typically made by divers or by remotely operated vehicles (ROVs).
Offshore industries are increasing their use of fiberoptic sensors and technology. The oil and gas industry has begun to adopt fiberoptic technology in order to provide reliable and high-speed communications connections to its subsea wells and production equipment. Fiberoptic cable technology is also being deployed to provide communications links from offshore facilities to onshore bases by way of submarine fiberoptic cables that run from the offshore site to the shore and then connecting to terrestrial fiberoptic systems and networks.
Various governmental and scientific organizations are also beginning to use fiberoptic cables and subsea connectors to access a wide variety of cables, sensors and subsea systems. As with the oil and gas industries, these connections are being made in ever increasingly deep water. This makes the deployment of the fiberoptic cables more complex and more expensive. In particular, it is a major challenge to get the fiberoptic cable from the surface, through the water column and to the sea floor in a reliable and cost effective manner. This challenge increases with the depth of the water in which communications equipment is to be placed.
One method of quickly connecting fiberoptic systems to the cables and equipment on the sea floor involves the use of a dedicated cable system. This is commonly known as a xe2x80x9criser.xe2x80x9d These risers are designed to be permanently installed on the structure so as to access the fiberoptic system below the surface. These risers are generally long lead time items. These risers must be permanently installed at a considerable expense. In the event of failure, the riser system may be offline for extended periods of time while replacement risers are being produced and installed. There is a need in the industry to provide the offshore industries with a simple cost-effective method of delivering a fiberoptic cable to the sea floor with a reusable and easily deployed device that can be quickly replaced or repaired.
Various patents have issued relating to such systems. For example, U.S. Pat. No. 6,350,085, issued on Feb. 6, 2002 to Bath et al., describes a cable deployment system and method of laying a cable on the sea floor. The cable deployment system includes a cable having a first cable section connected to the riser cable section. The riser cable section includes an arm that is connected to a drum capable of containing the required length of the first cable section. A stinger is attached to the drum and shaped to allow the first cable section to exit the drum. The cable deployment system also includes a tension device attached to the drum. The tension device is capable of maintaining a tension in the first cable section during the deployment of the first cable section from the drum. The method of deploying the cable in deep water from the surface includes the steps of containing the first cable section within the drum and lowering the drum from the surface vessel. An end of the first cable section is secured to the sea floor and the first cable section is deployed from the drum onto the sea floor.
U.S. Pat. No. 5,807,026, issued on Feb. 19, 1998 to J. M. Valette, teaches a device for pulling the end of a fiberoptic cable. This device includes a hollow anchoring body having an axial passage formed in the front end thereof suitable for receiving an end of the cable. The anchoring body has an integral hollow cylindrical skirt coaxially extending rearwardly therefrom. The skirt receives an axially positioned insulating ring and a clamping assembly that is located radially inwardly of the ring. A removable hollow cover axially abuts the anchoring body and covers the cylindrical skirt. A terminal plate is located at an end of the hollow casing opposite the cylindrical skirt so as to connect stripped fibers thereto.
U.S. Pat. No. 5,755,530, issued on May 26, 1998 to D. L. Garren, teaches a cable laying apparatus for an underwater cable burial machine. This apparatus utilizes a pivotally liftable depressor wheel located within a feed shoe which tracks the groove by the plow. A pair of arcuate cable guides assist the guidance of both cables and bodies without permitting either to bind. When the assembly to which the depressor wheel is attached is raised upward and rearward, the guides prevent the cable from escaping while allowing a body to pass through the opening which is formed.
U.S. Pat. No. 5,748,102, issued on May 5, 1998 to T. D. Barron, describes an apparatus for connecting an underwater vehicle and a free floating communications pod. This apparatus includes a communication cable depending from the pod and extending to a buoy of greater buoyancy than the pod. The cable carries communication signals between the pod and the buoy and extends generally vertically in a column of water between the pod and the buoy. The buoy is in communication with a distal station. The apparatus further includes a mobile unmanned underwater vehicle having therein guidance means for directing the vehicle to the cable. The vehicle is in communication with a control vessel. A connector means is mounted in a nose section of the vehicle and is adapted to intercept the cable. The connector means further is adapted to permit the cable to slide therethrough as the vehicle continues movement after intercepting the cable. A complementary alignment means on the vehicle and the pod is adapted to cause the vehicle to engage the pod in a pre-selected orientation and azimuth. When the communications component of the underwater vehicle and the pod are in alignment, the control vessel will be in communication with the distal station.
It is an object of the present invention to provide a simple and cost effective method of delivering a fiberoptic cable to the sea floor with a reusable and easily deployed device that can be quickly repaired and replaced.
It is another object of the present invention to provide a method of deploying a fiberoptic cable for which the communications connections can be established in a very fast manner.
It is further object of the present invention to provide a fiberoptic cable management system and method whereby the cable can be easily connected and disconnected from a subsea communications connection.
These and other objects and advantages of the present invention will become apparent from a reading of the attached specification and appended claims.
The present invention is a method of deploying a communications cable below the surface of a body of water comprising the steps of: (1) loading the cable around a reel within a housing so as to have a connector positioned at an end of the cable; (2) lowering the housing and the reel into the body of water for a desired distance; (3) retrieving the connector of the cable from the housing; (4) moving the connector and the attached cable to a position away from the housing; and (5) connecting the connector to a subsea communications connections.
In the present invention, the housing and the reel are positioned off of the side of a structure positioned above the surface of the body of water. The cable is connected to a communications device on the structure. An umbilical line is extended over a crane structure on a side of the structure. This umbilical line is electronically connected to the communications cable. The umbilical line is secured through a winch positioned on the structure. The winch is rotatable so as to lower the housing and the reel into the body of water.
In the present invention, the structure that is located above the body of water can be either an offshore oil rig or a vessel. The reel is actuated so as to unwind the cable from the reel such that the connection moves away from the housing.
In the present invention, the step of retrieving includes deploying a remotely operated vehicle below the surface of the body of water and intercepting the connector by the remotely operated vehicle. The remotely operated vehicle is controlled so as to deliver the connector to the subsea communications connection. Alternatively, the present invention can utilize a diver in place of the remotely operated vehicle if the subsea connection is not too deep below the surface of the water.
Also, the present invention includes the step of releasing the connector from the subsea communications connection, reeling the communications cable and connector back into the housing, and then lifting the housing and reel outwardly and above the surface of the body of water.
In the present invention, the communications cable is a fiberoptic cable.